Let vp×q be rectangular (i.e., not square) such that its columns are orthonormal. What can be said about v∗v and vv∗?

a) v∗v = I_p, vv∗ = I_q
b) v∗v = I_q, vv∗ = I_p
c) v∗v = I_p×p, vv∗ = I_q×q
d) v∗v = I_q×q, vv∗ = I_p×p